Pest Management Science (2018) 74, 2747-2753

Sarah Morran, Marcelo L. Moretti, Caio A. Brunharo, Albert J. Fischer and Bradley D. Hanson (2018)
Multiple target site resistance to glyphosate in junglerice (Echinochloa colona) lines from California orchards
Pest Management Science 74 (12), 2747-2753
Abstract:
BACKGROUND
In California specialty cropping systems such as vineyards and orchards, Echinochloa colona is present as a summer annual weed. It is able to germinate throughout the growing season whenever favorable conditions are present, and management relies heavily on glyphosate applications. Glyphosate-resistant (GR) E. colona biotypes are present in the state, but the levels of resistance observed suggest that there may be differences in mechanisms of resistance among populations.
RESULTS
Echinochloa colona lines collected from different regions of California's Central Valley presented resistance levels ranging from 1.4 to 4.3-fold compared to susceptible lines. No differences in the absorption and translocation of [¹⁴C]-glyphosate were observed among lines. Resistant lines accumulated eight-fold less shikimic acid after treatment with 435 and 870 g a.e. ha^-1 glyphosate compared to the most susceptible line. Sequencing of a region of the EPSPS gene revealed three single nucleotide changes leading to amino acid substitutions at Proline 106, including Pro106Leu, Pro106Thr and Pro106Ser.
CONCLUSION
These results indicate that an altered target site in EPSPS is contributing to resistance in these lines and resistance has evolved independently, multiple times in the Central Valley of California. Additional research is needed to further understand the genomic contributions of resistance loci in this polyploid weed species.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Albert J. Fischer

Research topic(s) for pests/diseases/weeds:
pesticide resistance of pest

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Echinochloa colona (weed)	Grapevine (Vitis)	U.S.A. (SW)